Textile sheet material



Dec. 18, 1956 H. A. sEcRisT 2,774,127

TEXTILE SHEET MATERIAL Filed OCT.. 24, 1950 @gw A INVENTOR. flo/@HCE f7. ge/@fw fifi-5177-5 United States Patent 0 F TEXTILE SHEET MATERIAL Horace A. Secrist, Dedham, Mass., assignor to The Kendall Company, Boston, Mass., a corporation of Massachusetts Application October 24, 1950, Serial No. 191,933

5 Claims. (Cl. 28-79) This invention relates to conformable textile sheet materials which consist in part of bers which have been Vspun into yarns and in part of integrated unspun ber masses.

In the past composite structures of spun and unspun bers have been produced by adhesively joining woven fabrics to loosely associated ber masses or to adhesively bonded non-Woven brous sheets. The adhesive connections have consisted of ber-to-ber and ber-to-yarn bonds created by saturating or impregnating the assembly with elastomeric or other resinous substances or by activating potentially adhesive bers contained in the structure. In some instances woven basesand brous Vbodies have been loosely connected by mechanical techniques. Because of the low degree of frictional entanglement, however, the ber anchorage is usually so poor that these structures have unsatisfactory abrasion or delamination resistance unless they are further united by positive adhesive bonding between the bers andthe yarns. If the composite fabrics have been saturated or impregnated with cementitious substances, the porosity of the structure as a whole is commonly reduced and its absorbencyand softness are usually greatly diminished. In those cases where potentially adhesive bers have been used as bonding agents, the pressure usually employed during unication of the assembly mats down the bers causing a similar loss in bulk,.softness and porosity. In such prior structures, the dominant characteristics of the Woven base fabric largely control the physical properties of the productbecause the low extensibility of the woven Yfabric and its adhesive bonding to the unspun bers mize freedom vof ber movement.

It is the primary object of this invention to provide a unital structure of spun and unspun cottom bres which, in itself, has sufcient integrity ,to obviate the necessity for adhesive binder materials.

It is a further object of this invention to'provide an A integrated structure of spun and unspun cotton bers which has extensibility (much or little as may be desired), exceptional stress distribution capacity, conformability, elastic return, and substantial tensile strength When the limit of its normal extensibility is approached.

It is a still further object of this invention to provide a soft, exible sheet material of spun cotton bres ,and self-integrated masses of unspun cotton bres, the unspun bers being arranged at one or more surfaces of the sheet material.

I accomplish these objects, and others, by supplying a novel unital fabric comprising spun and unspun bers, the fabric being characterized by frictional entanglement and interlocking of the unspun bers with each other and with the spun bers, individually, collectively, or both, as a result of articially induced kinks, bends, twists and curls in a portion at least of the unspun bers, with or without the same in the spun bers. ln my preferred structures the yarns exhibit random kinks, bends, loops and twists, further enhancing the integration Ofthe spun andiunspun'bers but, in various useful products of sub- 2,774,127 Patented Dec. 1 8,

ice

stantial integrity, yarns may .be practically straight or exhibit only a slight crimp.

These and other characteristics of my invention will be more readily appreciated from the following description of several embodiments thereof selected forrthe purpose of illustration and shown in the accompanying drawings, in which:

Figure 1 is a plan view of a section of fabric in accordance with one embodiment of my invention.

Figure 2 is a cross section along line 2-'2 of Figure 1.

Figure 3 is a plan view of another fabric according to my invention, one corner of the fabric being sectioned in the plane of the yarns, and the upperlayer of unspun bers being rolled back upon itself. Y

Figure 4 is a cross section along line 4-4 of Figure 3.

Figure 5 is a plan view of a secion of a fabric in accordance with another embodiment of my invention.

Figure 6 is a cross section along line 6`6 of Figure v5.

Referring to the drawings, the fabric comprises a composite of spun bers or yarns 10 and unspun bers 12. The spun bers 10 may be randomly disposed as shown in Figures 1 and 2, or may be woven into fabrics as shown in Figures 3 and 4, or may be knitted as shown in Figures 5 and 6, or may be netted or otherwise disposed. The spun bers 10 are in commingled relationship with the unspun bers 12. The yarns or unspun'bers 12 are mutually integrated and are in apposition with the spun bers 10, as a result of the kinks, bends, twists and curls of unspun bers 12. y

' Substantial ber freedom is maintained in the association of yarns and unspun bers in the basic fabric because no bonding agents are required to lock the bers into any xed orientation or arrangement; however, the frictional engagement and entanglement of the unspun bers with each other and withkthe spun bers is substantially continuous and uniform throughout the sheet and contributes unusual tensile characteristics to the sheet material. The preferred products of ythis invention possess conformability and extensibility due, it is thought, to the capacity of the curled unspun bers to straighten, extend, slip past each otherand assume new positions of entanglement coupled with the stress distribution action of the spun bers. In general, typical novel sheet materials ofmy inventionmay be extended 25% in either direction without any appreciable'destruction of` integrity, although, in some instances, depending on Vthe yarn construction and conditions of treatment, the extensibility is considerably less, while in my preferred structures the extensibility is generally or better and elongations at break of as high as have been noted. Unlike conventional materials of high extensibility which tend to rupture with only slight increases in stress as their stretch limits are' approached, many or most of my products exhibita high ultimate strength in one or more directions when the limit of ready deformation is reached, and substantial increases in deformation stresses produce only slight additional elongations.

When my preferred sheet materials are subjected to tension along either of their axes, the structures display a relatively high initial resistance to deformation, and

thereafter the elongation is relatively large for small load my fabrics W'itha substantial degree of elastic return.

f 3 i' The strength, elastic confomability and capacity for stress distribution of my novel products in combinatlon with their capacity to receive large quantities of saturants or irnpregnants adapts them for use as base materials in v cause they lackY the extensibility and conformability for three-dimensional yield without 'failur e. `Fibfrous bats and otherfnon-woven'ibrous sheet materials which are frequently used for this purpose, although they may possess the Vnecessary extensibility and conformabilityY to yield without rupture, lack the stress-distribution capacity foi' uniform, smooth deformation. As a result, even if'com-V plete' failure of such non-woven base materials is avoided, the'linished deep-drawn'products .have pronounced thick and thin spots, are unsightly in appearance and susceptible to failure under furtherY stresses. Y Y

In my novel sheet materials, including a layer or layers of yarns, the yarns, so to speak, act as conductors of stress away fromstressed local areas Yso that when my products are subjected to tension and/orV twoor threedimensional deformation stresses, the load is distributed throughout a larger zone of the structures rather `than'c'sarried by single fibers or local groups of fibers, and the occurrence of thick and thin spots is minimized.V

Because the natural softness and absorbency of the cotton fibers need not be destroyed or inhibited by the addition of bonding agents, many of my structures have general utility in the medical and surgical'ieldas dressing and bandaging materials, particularly when appreciableV tion of wounds with non-cellulosic material which mayv be of an irritating or toxic character. As lpolishing cloths or as applicators for wax, shoe polish, cleaningcompounds and the like,vthe products Vof this invention are highlyV` satisfactcry.f Their .ready conformability enables them to be ldrawn about polishing blocks or plates without fabrio rupture and the fiber absorbencyvand thehigh per' .centage of voids inthe structures permits the introduction ofY large amounts of polishing or cleaning mediums. Since my products consist entirely, orV mainly,A of cellulose, they are particularly useful as industrial 'filters 'or Vin othersimilar applicationswhere a high resistance Yto the action of a wide variety of inorganic or organic sol-V vents is required. Fibrous materials which contain binder Vmaterials Vor which have been reinforced with or I aminated to woven fabrics bymeansof added binding agents are restricted in their usefulness for iiltering-purposesbecause of the danger that the liquid to be liltered may dissolve the binder materiaL-thereby weakening the filter vstructure and contaminating the liquid.

Preferably, Irprepare the novel fabrics of my invention in the followingmanner. One or more uns'pun cotton trolled shrinkage of the structure, depending on thecharacteristics desired inthe final product; The integrated assembly is then washed to remove the swelling agent and dried. The preferred treating chemical of jthe process is an aqueous solution of caustic alkalisuch asfsodium, po-

"tassium, or lithium hydroxide, but other basicV cellulose swelling agents may be employed, such as solutions of sodium zincate, quaternary ammonium bases such as benzyl trimethyl ammonium hydroxide and the like.

An apparatus which may be employed in the'manufacture of my products is disclosed and more fullyv described in my copending application,fSerial No. 151,512, led March 23, 1950, now Patent No. 2,688,864.

Using aqueous sodium hydroxide solutions satisfactory results have been obtained with solution concentrations of at least 8% and less than30% NaOH at temperatures from just above the freezing point of the solution to +25 C. Temperature and concentration are mutually dependent variables, and Vthe selection of a particular value for one may fix the operating range of the other.v

Preferably and for best results such solutions are used in concentrationrof at least 10%V and less than 18% VNaOH at temperatures from 10 C.A to +15 C. Other reagents may be employed at corresponding elfectve strengths and temperatures.

The maximum felting, contractive etfectsof the chem calare realized in a shorttime, normally in 1/2 to 3 minutes, and the sheet material s Vthen removed from the vat and treated to remove fthe chemical, .preferably promptly as over-long exposure to the chemical, especially in air, may produce secondary changes'in thebers which i may give undersirable results. f

f The chemical solution is4 washedrfrom the Vshrunken sheet material preferably byowing a large quantity of water through it while it is carried on amoving screen or like A structure through which the liquid drains. Prefer-V ably; although not necessarily, the alkaline. residue ,is then neutralized inV acid or other suitable agent, such'as acetic acid or sodium bicarbonate,'and the sheet material is again washed.Y The ibroussheet material washed free of treatingV chemicals is finally Vdried to complete the.

process. If high residualrstr'etchability'is undesirable crunnecessar'y, as for example in kthose instances in which my sheet materials are to .beV usedaspolishing or wiping cloths, integral products of limited extensibility infone orfboth directions, may be manufactured either byre strictng the shrink of the assembly by varying the yarn construction or the treating conditions, or by Vwet-stretchit may take the Vform of yarns laid inthe warp direction only, inthe filling direction vonly or otherwise positioned with the unspun liber constituent. Y r

rIn structures embodying a knitted yarn layer or layers, the high degree of freedom VVof theknitted yarnspromotes particularly good .interaction between` the yarnsV and unspun fibers during my treatment'but also deprives these structures of the sharply defined limit lof extensibility which is desirable for some purposes. Y'

v Either the Yyarns or the unspun fibers may predominate `at one surface or at both surfaces of the'structures and' various multiple structures may be manufactured depending on-the number and orientation of the spun and unspun elements. `*Figures 3 and 4 show theyunspunibers 12 predominatelyat both surfaces of the-fabric, and Figures 5 'and 6 show thespun `bers or yarns 10 predominately at one surface ofthe fabric. AIn jthose structures-where l yarn-arrangements other Ythan wovenvonknitted'fabrics areemployed it may be preferredthat thespun bers be'buried in the interior of the material for VLthesakeof more uniformappearance, and/orsurface characteristics, integrity,fetc. Y Y Y 'Y i In any case, it isV emphasized'that thev'novelwfabtics his of the present invention are unital structures in which the constituent parts are mutually integrated by the articially-induced interlocking ber congurations.

When the assembly is treated with caustic, the unspun bers writhe, curl, twist and loop in all three dimensions, entangling themselves with each other and with the spun bers to which they are in apposition, the unspun bers in some cases penetrating the interstitial yarn spaces and looping around the yarns, and the frictional engagement of the two types of bers being further increased in my preferred structures by the contractions and distortions of the yarns and the entrapment of unspun bers between kinks and bends of the yarns.

I prefer open-mesh fabrics as the sun-ber constituent of my structures because they permit high area contractions and maximum integration with the unspun elements. However, useful structures of integrity sufcient for many useful purposes may incorporate closely meshed yarns. If the yarns are arranged otherwise than by weaving or knitting, the same general considerations apply.

In the manufacture of my products I have found it commercially expedient to employ unspun ber layers ranging in weight from ve grams per square yard to 150 grams per square yard. In order to attain various objects of this invention, it is necessary only that spun bers be present in significant amounts.

While the products of this invention are prepared by chemically treating spun andV unspun cotton bers, and such products are primarily dependent for their structural integrity on the presence of interlocking cotton bers, it is possible to prepare many useful articles in which other bers may be dispersed in minor proportion provided that they do not seriously interfere with the interlocking of the cotton bers. These additive bers may be cellulosic or non-cellulosic, thermoplastic, natural v or synthetic bers, such as kapok, wool, silk, vinyon, nylon, and regenerated cellulose. If desired, rubbercored yarns may be employed.

In the preparation of my unspun brous web constituents I usually employ cotton bers of suicient length to be handled conveniently on textile machinery such as cards or garnetts. However, the ber length is not critical provided that the bers can be assembled pneumatically or otherwise into webs suiciently coherent to be processed by my caustic treatment and the ber length-to-diameter ratio is suciently large to permit adequate entanglement of the bers with each other and With the yarns.

To illustrate further suitable preferred practice of the process of my invention and production of various novel fabrics thereof, the following examples are given:

Example 1 Webs of cotton bers from two cards were superposed to form a brous sheet weighing grams per square yard. Between two such sheets was placed a coextensive layer of 14 x 10 open mesh, bleached cotton fabric woven of s and 40s yarns in the warp and lling respectively. The assembly was lightly pressed by passing it through nip rolls under a pressure of about 10 pounds per inch of roller width and then treated in a 16% solution of sodium hydroxide at a temperature of 2 C. After a treating period of seconds the structure was removed from the bath by means of a moving screen, rinsed with water, neutralized with acetic acid, again washed, and nally dried on dry cans. An area shrink of the order of 85% was noted. As a variation of this example, the woven fabric might have been at both surfaces with the brous sheet therebetween.

Example 2 A ply from a 45 grams per square yard header roll of superposed webs of bleached, carded cotton bers was lightly pressed to a layer of 18 x l2 cotton gauze and the assembly treated in 18% caustic at 10 C. After the integrated sheet material was washed with water, neutralized with acetic acid, rewashed with water and dried on a steam can, an area shrink of approximately 75% was noted.

Example 3 Example 4 A layer of cotton from a header roll and a coextensive piece of 14 x l0 raw cotton fabric (of 30s and 40s yarns having normal twist) in the loom state, i. e. with sizing on the warp yarns, were lightly pressed together and dropped into a tank containing 11.8% NaOH at 0 C. and a small amount of a suitable wetting agent. The resulting area shrink, after washing and drying of the material, was 78%. f

Example 5 A layer of 18x12 open-mesh, bleached gauze was lightly pressed to a piece of like area from a header roll of carded bleached cotton weighing 45 grams per square yard and the assembly looped onto a pin frame so as to limit the ultimate shrink to 25% each in the warp and lling directions, or an area shrink of 44%. bination was then dropped into a tray containing 16% NaOH at 2 C., a diffusion screen placed on top of the sample, and additional caustic solution poured over the screen. The sample was then given a dilute acid wash, a water wash, a suction treatment to remove excess liquids, and dried on a steam can. In the integral nal product the yarns were nearly straight, exhibiting only a slight crimp.

Example 6 A ply of bleached cotton header roll weighing 60 grams per square yard was lightly pressed to a layer of 44 x 36 cotton gauze of 30s and 40s yarns and the assembly treated in 16% caustic at 2 C. After the integrated sheet material was washed with water, neutralized with dilute acetic acid, rewashed with water and dried on a steam can, an area shrink of the order of 70% was noted.

Example 7 Fourteen strands per inch of 30s cotton yarn were positioned between two carded, bleached cotton ber sheets each weighing 30 grams per square yard and the aggregate treated in 16% caustic at 2? C. The resulting area shrink, after washing and drying of the material, was 80% Example 8 Example 9 A ply of 80x80 cotton print cloth and a coextensive piece weighing 45 grams per square yard from a header roll of bleached, carded cotton bers were lightly pressed together and treated with a solution of 16% NaOH at 2 C. After washing and drying, the nal area shrink was about 30%.

Example 10 At some sacrice of various desirable characteristics of my products, particularly high integration, one can employ bers of regenerated cellulose as the spun ber con- The comstituent. However, when employing Vsuch fibers, less severe caustic'rtreatment is in order, thatis, the solution temperature should be in the range fromV 15 to 25 C.,

and the caustic concentration between 16 and 30 percent. If a soft, exible material is desired, it is advisable to add to the Wash predetermined amounts of an inorganic salt soluble in dilute caustic. I have'produced a satisfactory ated cellulose spun bythe Viscoserprocess and treating the assembly in a bath of 20% NaOH at 23 C.` The material was washed in water containing sodium chloride, rewashed in water, and dried. 'The nal area shrink was approximately 575%. 1 Iclaim: Y f l. As an article of manufacture, a unital, coherent, integrated, shrunken textile sheet material having substantial extensibility, ,conformabilityg integrity, and resilience Vand consisting essentially of cotton fibers spun into yarns andrinv apposition therewith unspun cotton fibers which are chemically-swollen, said spun {bers and said unspun fibers being mutually integrated and frictionally interlocked by chemically inducedV permanent deformations of the said unspun Yfibers, said deformations being in the form of random kinks, bends, twists, and curls in substantially all three dimensions and being in excessof the deformations normally present in cotton bers, the unspun fibers being entangled with themselves and with each other and with the spun fibers to which they are in apposition, the entanglement being substantially continuous and uniform throughout the sheet. Y

4. As-an article of manufactureQa sheet material as v defined in claim 1 having anl extensibility of at least 255% in one direction without appreciable loss of integrity.

5. Asan articleof manufacture, a unital, coherent,V integrated, shrunken Vtextile sheet materialrhaving substantial extensibility, conformability, integrity, and resilience Y,

' and consisting essentially'of cotton fibers spun into yarns product by lightly Vpressing together a layer of bleached Y carded cotton header roll and a 20x12 fabric of regenerin substantially all three dimensions and being in excess of the deformations normally present in cotton fibers, the' unspun iibers being entangled withY themselves and VVWith'V 2. As'an article of manufactuiea sheet material ac cording to claim l in which the yarns are arranged in the form of an open-mesh woven fabric.

3. As an article of manufacture, .a sheet material ac- VYcording to claim 1 in which the yarns are arranged in the form of'an open-mesh, knitted fabric.V

and in apposition therewith unspun cotton fibers which are chemically swollen, said spun iibers and said unspun fibers being mutually integrated and frictionally interlocked by chemically induced permanent deformations of the said unspun bers and spun bers, said deformations being inthe form of Vrandom kinks, bends, twists, and curls each 'other' and with the spun bersvto which they are-in apposition, the entanglement being substantially continu-V ous and uniform throughout the sheet.

References Cited in the le of this patent UNITED STATESPATENTS Great Britain 'of 1903 

1. AS AN ARTICLE OF MANUFACTURE, A UNITAL, COHERENT, INTEGRATED, SHRUNKEN TEXTILE SHEET MATERIAL HAVING SUBSTANTIAL EXTENSIBILITY, CONFORMABILITY, INTEGRITY, SID RESILIENCE AND CONSISTING ESSENTIALLY OF COTTON FIBERS SPUN INTO YARNS AND IN APPOSITION THEREWITH UNSPUM COTTON FIBERS WHICH ARE CHEMICALLY SWOLLEN, SAID SPUN FIBERS AND SAID UPSPUN FIBERS BEING MUTUALLY INTEGRATED AND FRICTIONALLY INTERLOCKED BY CHEMICALLY INDUCED PERMANENT DEFORMATIONS OF THE SAID UNSPUN FIBERS, SAID DEFORMATIONS BEING IN THE FORM OF RANDOM KINKS, BENDS, TWISTS, AND CURLS IN SUBSTANTIALLY ALL THREE DIMENSIONS AND BEING IN EXCESS OF THE DEFORMATIONS NORMALLY PRESENT IN COTTON FIBERS, THE UNSPUN FIBERS ENTANGLED WITH THEMSELVES AND WITH EACH OTHER AND WITH THE SPUN FIBERS TO WHICH THEY ARE IN APPOSITION, THE ENTANGLEMENT BEING SUBSTANTIALLY CONTINUOUS AND UNIFORM THROUGHOUT THE SHEET. 